<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>

</head>
<body>

<select name="pro" id="s1">
    <option>请选择省份</option>
    <option value="111">河北省</option>
    <option value="222">河南省</option>
    <option value="333">东北省</option>
</select>

<select name="pro" id="c1">
    <option>请选择城市</option>

</select>

<textarea id="t1">

</textarea>


<script>
    var ele_select=document.getElementById("s1");
    ele_select.onchange=function () {

      console.log(ele_select.value)

    }
</script>


</body>
</html>